1. Field of the Invention
This invention relates to a power-spring assist to the pedals of a bicycle. Engagement of the spring assist is controlled by the rider by means of a throttle hand grip mounted on a handle bar of the bicycle. By turning the handle grip, the rider can release torque from the power-spring to the bicycle pedal assembly where it will, in turn, provide power to the rear wheel as needed, for example, when going uphill, or riding against a head wind. The rider of the bicycle can charge the power-spring when convenient, for example, while pedaling downhill or on the level. Alternatively, in a preferred embodiment, the rider can charge the spring before embarking by engaging a kick-stand to hold the bicycle in a stationary position by lifting the rear wheel off of the ground.
2. Description of the Prior Art
Already known in the art from U.S. Pat. No. 5,035,678 is the use of an energy-storing bicycle sprocket wheel drive system mounted to the bicycle pedal crankshaft. This system is mounted entirely on the pedal crank assembly and provides for the storage and release of energy at various points during each turn of the pedal crank. U.S. Pat. No. 1,408,459 describes a spring-powered bicycle in which the foot pedals charge a spring and the spring powers the rear wheel of the bicycle. The foot pedals move in an arc independent of each other, and the rider charges the spring by force to either or both of the pedals. There is no direct connection between the pedals and the drive wheel. Neither system allows the rider to charge the spring and release the spring energy at the convenience of the rider.
Also known in the art from U.S. Pat. No. 4,146,464 is a spring assist drive for a bicycle or tricycle which discloses a coil spring assembly, but this assembly functions as a continuous permanent operating drive, and is not selectively engagable by the rider. The coil spring cage is located above and to the rear of the axis of the rear drive wheel. The mechanism disclosed in this patent differs from that of the present invention.